Use set-gpg-id as command for setting the public key identifier

This commit switches the command for setting the public key identifier
to set-gpg-id. Previously it was set-pub which might be confusing as no
actual public key was set.

Signed-off-by: Lars Kiesow <lkiesow@uos.de>
Use set-cipher command for setting-up a special cipher for a channel

Signed-off-by: Lars Kiesow <lkiesow@uos.de>